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The Mad Fermentationist

Monday, July 22, 2013

Three years ago I did a post on my basic homebrewing process. Since then it has been of the most popular pages on the blog. Several people have told me that it really helped them to see an example of a complete process, rather than reading a book that can be overwhelming with several options for each step.

In a similar vein, I thought I'd walk through a brew day at Modern Times. This won't be enough specificity for you to brew a batch on our Premier Stainless Systems 30 bbl brewhouse, but hopefully it is enough to give you a flavor of what a batch on a two vessel craft system is like. This particular batch was the third of Lomaland saison.

Alex "Captain Kunindra" Tweet walked me through the first half of the brew, before our head brewer Matt Walsh arrived to finish things up. Ironically Alex's first all grain batch a few years ago was a recipe posted on my blog (shortly before he swept the Ballast Point competition that earned
him his nickname). Matt has been a brewer for years, starting at Alesmith before stints as head brewer at Karl Strauss, Speakeasy, and most recently Lost Coast.

Excuse the photo quality, I brought along my DSLR, but left the memory card in my computer. As a result I had to shoot with my phone.

This big red box is our hot liquor tank (HLT). Purchased secondhand, it is automatically controlled to keep a supply of hot water ready to use for the mash, sparge, and cleaning.

We waited until the water in the HLT reached 170 F before mashing in because while water is being sent to the brewhouse, the HLT stops heating.

The night before Alex milled in nearly all of the malt (pale, Pilsner, and acid) followed by the flaked wheat and corn through the trap door in front of the mill. The grist is conveyed by an auger to the hopper in the center of the picture.

Here is the control board for the mash tun, there is a similar one for the boil kettle, and another for the fermentors. At the moment nothing has been switched on.

Here is the mash tun. The "rakes" on the right side are raised or lowered manually. They stir the mash, and are used to clean out the mash tun. Running the rakes down with the mash tun full of spent grain can cause serious damage.

Unlike homebrewing where the mash water is heated in its entirety to a specific temperature, here the water from the HLT is cut with cold water (via the black-handled valve) to reach the desired temperature as indicated by the thermometer at the top.

To get hot water to the brewhouse we hit the HLT to Brewhouse button. This stops additional water from being added to the HLT or heating.

The clean in place (CIP) is opened so that the hot water is sprayed over the interior of the mash tun to pre-heat it to the target mash temperature.

The valves below the mash tun are opened to allow this pre-heating water to drain. The door used to empty the spent grain is also cracked to allow the hot water to drain.

Here you can see the hot water spray on the manway of the mash tun.

The temperature slowly rises over about 15 minutes.

The hot water drains.

He dials in the speed of the pump that delivers water to the mash tun. The auger that carries the grain operates at a fixed speed, so we have to adjust the water delivery to reach the desired mash ratio. A slow flow rate can also cause the grist to jam up as it mixes with the water. The same readout also provides the total amount of water added.

And closes the valves, to begin trapping water in the mash tun.

About 100 gallons of water is allowed to enter the mash tun without any grain. This lays a foundation so that grain is not forced down onto the false bottom that serves to separate husks from wort during lautering.

Alex continues to dial in the temperature to reach the target, about 11 F above the mash temperature (149 F).

Our flow rate (gallons per minute).

Right on target (after a minute or two of fiddling).

The rakes are turned on to stir the mash.

Once the temperature is on target, and the foundation water has been laid, the auger is switched on to deliver the crushed grain.

The door is slid out to allow the grain to mix with the hot water as it enters the mash tun.

He fiddled with the cold water to get the temperature just right as is seemed to be coming in a degree or two high.

When the grain is almost drained from the hopper, Alex ground a final bag of pale malt to ensure all of the specialty malts were "chased" out. This is especially important when brewing a darker beer, as it doesn't take much dark malt trapped in an auger to affect the color and flavor of the following beer.

Crushed grain passing out of the storage hopper and into the auger that carries it to the mash tun.

The mash tun as it fills with hot water and grain.

When all of the grain is in the mash tun, we continue to run the water until we hit the target volume.

The hop extract used for bittering is put onto the boil kettle in advance so it warm up and liquefies (it is very thick and syrupy right out of the cold box).

The valves are opened to allow wort to flow via gravity from under the plates of the false bottom and into the grant.

More valves are manipulated to allow wort to be pumped from the grant back into the top of the mash tun, preparing to vorlauf.

After the 20 minute mash rest, here is what the wort looks like.

The mash tun has two sight glasses to allow us to gauge how the wort is flowing through the grain bed. The one on the left shows the pressure above the plates, and the one on the right is below (it would much easier to see with a stout). If the one on the right is just a few inches below the one on the left, then things are running smoothly. In the difference is greater, then the wort isn't flowing well and you may be in for a stuck vorlauf/sparge.

The valves and pump speed are adjusted so that the wort flows into the grant at the same rate it is pumped out. This is the easiest time to get the flows equal so it does not need to be adjusted later.

After 20 minutes of vorlaufing the wort is flowing much clearer.

Here is the empty boil kettle. The hole at the bottom is for cleaning, wort headed to the chiller will exit the hole at 1 o'clock.

He moves the valves to pump the wort from the grant to the kettle instead of back into the mash tun.

He takes the gravity of the first runnings.

Our final mash temp is only .4 F below our target. It is easy to over-correct. Initially the temperature appeared low, then high. Trusting the water temperature calculations are key, any adjustments need to be slow and subtle.

As enough wort flows into the boil kettle to cover the bottom we turn on the kettle's bottom steam jacket. Unlike many smaller breweries (and 99.99% of homebrewers), steam from a boiler heats the kettle rather than a direct flame or electric element

When the wort drops to level of the grain bed, we begin to sparge with 170 F water. The goal is the keep the sparge water flowing at a rate the keeps it just an inch or so above the grain bed.

As the sparge continues, and the kettle fills, we turn on the other jackets to speed the heating.

When the sparge is complete (signaled not by volume, but by the runnings reaching 2P, 1.008), the spent grain is allowed to drain. When it is reasonably dry, a hopper is positioned under the door.

The door is opened and the spent grain is allowed to spill out (and then encouraged to do so with the rakes).

Once the wort reaches a rolling boil we pull a sample to test the gravity.

We were slightly under volume, but over-gravity, so we added one barrel of hot water. Then a few pumps of foam control followed by 30 IBUs of hop extract (the tins are rinsed to get every drop of extract out).

With 20 minutes left in the boil yeast nutrient and Whirlfloc are added.

A solid rolling boil.

After 60 minutes the steam jackets are turned off and 22 lbs of Saaz hop pellets are added.

There is no hanging out while we're brewing, any downtime (mash rest, sparge, boil etc.) are taken up by other chores like kegging.

After a five minute whirlpool and 20 minutes of settling, the wort is still at 210 F. This is the reason we were getting significantly more bitterness from our recipes on the big system than we ever did in test batches.

The valves are moved, and the connections are made to send wort to the sanitized fermentor.

With the wort ready to run off the oxygen in turned on to be shot into the wort in-line after chilling.

The water from the cold liquor tank (which is chilled to around 40 F) is running full blast to the plate chiller, so the pump speed for the wort is adjusted to achieve the target pitching temperature of 75F.

The oxygenated wort flowing through a sight-glass.

A sample of the wort, just a few tenths above our target OG of 12P.

With the fermentor filled, the line is pasteurized with water from the HLT (which was mostly refilled with "waste" water sent there from the heat exchanger) to prepare it to pitch the yeast.

The 100 L of yeast slurry harvested from Lomaland batch #2 is forced into the fermentor using CO2 pressure.

The now empty 100 L keg is then flushed with hot water to remove any residue.

A local farmer arrived to pick up the spent grain for animal feed.

The fermentor control board, showing we are a single degree under our target for fermentor #3.

Not too bad for six hours of work, especially because most of my time consisted of snapping photos while Alex and Matt did the actual work. When everything runs right brewing on a system like this is less physically taxing than brewing on a homebrew system (or it will be once we get a grain silo). Water and grain are conveyed by pumps and motors, but it's more mentally taxing. If things go wrong (valves in the wrong position, mechanical failure, stuck sparge...) it is a much bigger challenge to deal with. Not to mention the pressure that if you you ruin a batch it isn't $20 and a wasted Saturday, but thousands of dollars or the reputation of your brand.

Hopefully this gave you a taste of "the dream." I'll have a walk through of a day on the pilot system for anyone interested in a few weeks.

Nice post! Regarding your comment "After a five minute whirlpool and 20 minutes of settling, the wort is still at 210 F. This is the reason we were getting significantly more bitterness from our recipes on the big system than we ever did in test batches". Is that something you are shooting for, or something you're trying to dial back down?

Y'all are lucky to have rakes! I dream about them. We have the stir the mash by hand and then rake it out by hand. That accompanied with the direct-fired HLT and boil kettle makes the perfect recipe for heat stroke.

The additional bitterness was something we had to compensate for in subsequent batches. Luckily with 60 bbl tanks, we could just brew another 30 bbls of "under-bittered" wort to dilute the unexpected bitterness from the knock-out addition.

I've helped out at several breweries with more physical grain out processes. Luckily the brewers here pushed for a time saving additions.

This is a fantastic post, really interesting to follow along with the process.

A few questions, the Grant is just a tank with with you use to vorlauf correct? I only see the one dip tube in the grant, are the photos not allowing us to see wort in and wort out ports, or is something else going on?

The Auger is pump or some sort of conveyor thing? For some reason I cant wrap my head around pumping crushed grain.

So how would you rate the Premier Stainless setup? If you/they could go back and re-do their setup, would you still go with Premier or would you have considered using another brewhouse manufacturer/supplier?

The brewers certainly have a few complaints about the system (e.g., the door on the bottom of the mash tun leaks slightly) but they all seem relatively minor. I don't have enough expierience on other systems to really judge.

The wort flows via gravity into the side of the grant. It is then pumped from a hole in the center. This way you reduce the chances of creating a vacuum in the grain bed, as you might when pumping directly out of the mash tun. The auger is like a long corkscrew in a tube. As it rotates it carries the grain up.

Hot side aeration is an over exagerated concern, not something we worry about. Whirlpooling is actually pretty gentle compared to vorlauf and moving wort from the grant into the boil kettle.

We dump trub multiple times, but there is only one yeast harvest to collect enough cells for the subsequent batch. The yeast is stored in the cold box until brew day. We pull it out when we start brewing to let it warm up. No venting, although it often has developed some pressure by the time we are ready to pitch.

Still early to know how the blend will behave with multiple repitchings. Fermentation on bath 1 was sluggish, so we staryed with a fresh pitch for batch 2. Most likely it will be a number of batches/generations thing. We don't want to let the yeast profile drift much before getting it back on track. Once we are propagating in house it'll be much less expensive to start with a fresh pitch more frequently (if we need to). We may develop another beer that we brew once the blend has reached its limit for Lomaland.

How exactly is the mash temperature maintained while recirculating? I see the steam lights on the panel but no mention of how these were implemented.

How are the hoses cleaned and sanitized each time? Especially before filling kegs etc? Is it similar to how we do with starsan at home? Is it just a case of pasteurizing as you did before adding yeast?

The timing of everything is too beer/batch dependent to really get specific. It is a look and feel sort of thing to determine what is what. After crashing there is a lot of "gunk" that drops out before the yeast, then a layer of good yeast, and finally another layer of less desirable material. After harvesting, conicals are dry hopped, recirculated, and then dumped several times to remove the spent hops until they are ready to go into a bright tank for carbonation.

The HLT is heated by the boiler, just like the kettle.

With that much volume the mash really doesn't loose much temperature during the rest or vorlauf.

Running hot water through the hoses to pasteurize them is the primary method of sanitizing (including the kegging rig). Tanks are sanitized with peracetic acid.

I won't speculate on exactly how yeast propagation will be done, if there are specific plans I haven't been told.

Well written post, thanks for taking the time. I'm a R&D chemical engineer at a rather large company. Your system is very similar to our pilot plants that we run. Budweiser is probably similar to our big chem plants - much more automated.

You certainly could set the HLT to the target mash-in water temperature...but then you'd be colder than ideal for the sparge, or for pasteurizing lines. You'd also deplete the hot water faster, meaning that you might run out of water if you are double brewing, or cleaning tanks etc. This is what works at Modern Times, and not what is ideal for every situation/system.

RE: the mash, you said "Initially the mash temperature appeared low, then high. Trusting the water temperature calculations are key, any adjustments need to be slow and subtle...with that much volume the mash really doesn't lose much temperature during the rest or vorlauf."

Therefore I assume these things: (a) you typically employ a single rest temperature, in this case 149F; (b) you only occasionally have to make an adjustment after mash-in.

In cases where you need to make an adjustment, do you fire up the steam jacket? I figure you don't use cold or hot water for this purpose since that would mess with your desired gravity.

Modern Times now has added a few vessels to their system (including a jacketed mash mixer) so they can do step mashes (or heat up a low mash-in temperature). When I wrote this post, single infusion was really the only option. If the temperature was off before all the water was in they could adjust the hot-cold ratio to compensate.